How do secondary headaches help us learn more about primary headaches?

A headache is secondary when it is caused by another condition. The term is used to distinguish this type of headache from the primary headache disorders like migraine, tension-type headache, or cluster headache. Many medical conditions can cause headache, but there are usually clues in the medical history or examination to suggest secondary headache.

Explanation:

Primary headaches could be causing secondary ones. Like an aftershock.

answerdecreased blood pressure;

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